Фибоначчи

type mas=array[0..1000] of longint;
var a,b,c:mas;
n,m,i,j,k,x:longint;
procedure sumlong(a,b:mas;var c:mas);
var i,k:longint;
begin
fillchar(c,sizeof(c),0);
if a[0]>b[0] then k:=a[0]
else
k:=b[0];
for i:=1 to k do
begin
c[i+1]:=(c[i]+a[i]+b[i]) div 10;
c[i]:=(c[i]+a[i]+b[i]) mod 10;
end;
if c[k+1]=0 then c[0]:=k+1;
end;
begin
readln(n);
a[1]:=1;
b[1]:=1;
a[0]:=1;
b[0]:=1;
for i:=3 to n do begin
sumlong(a,b,c);
for j:=0 to b[0] do
begin
a[j]:=b[j];
end;
for j:=0 to c[0] do
begin
b[j]:=c[j];
end;
end;
for i:=b[0] downto 1 do
write(b[i]);
end.

uses
  strutils;
const
  max = 1000;
 
function sum(const a, b : ansistring) : ansistring;
var i, s, carry : integer;
begin
  result := '';
  carry := 0;
  for i := length(a) downto 1 do
  begin
    s := ord(a[i]) + ord(b[i]) - 2*ord('0') + carry;
    result := chr((s mod 10) + ord('0')) + result;
    carry := s div 10;
  end;
end;
 
var
  f1, f2, f3 : ansistring;
  i, n : integer;
 
begin
  f1 := dupestring('0', pred(max)) + '1';
  f2 := dupestring('0', max);
  f3 := dupestring('0', max);
 
  readln(n);
  // n := 145; // выведет 1454489111232772683678306641953
  for i := 1 to n do
  begin
    f3 := sum(f1, f2);
    f2 := f1;
    f1 := f3;
  end;
 
  writeln(trimleftset(f3, ['0']));
end.